Financial markets' doubts about the strength of the euro can be blamed on a lack of decisive action by the European Union, French President François Hollande said here Thursday after talks with Spanish Prime Minister Mariano Rajoy.

"We have put off decisions too much and that has provoked doubts," the French leader said at a joint press conference with his host.

The picture will become clearer after the EU summit in October, Hollande said.

The gathering of the heads of government of the 27-member bloc will follow a Sept. 6 meeting of the governors of the European Central Bank and a Sept. 12 ruling by the German Constitutional Court on the legality of Berlin's planned participation in a permanent EU bailout fund, the French president noted.

A report on the condition of Spanish banks - who are to receive up to 100 billion euros ($123.2 billion) in aid from Madrid's eurogroup partners - is also due in September, Hollande said.

Both leaders stressed that the adoption of the euro was irreversible.

"Neither the euro, nor the single market, nor the EU will take one step backwards," Rajoy said.

Spain has made "great sacrifices" to reduce its deficit, but the spread between Spanish bonds and benchmark German bonds remains wide, Hollande pointed out, while Rajoy said Madrid will wait to see what the ECB will do to reduce the spread before deciding on whether to seek a broader aid package from the EU.

The prime minister denounced as "malicious" rumors circulating in Spain that his government is putting off asking the EU for more help until after regional elections in October.

The Spanish political class is looking toward those elections, in Galicia and the Basque region, as indicators of the degree of public discontent with tough austerity measures enacted by Rajoy's conservative administration since taking office last December.